The easiest way to start is to stop eating all processed/ultra-processed foods (which include ready meals, crisps, sausages & bacon, shop-bought cake, sugary drinks, etc). Also eliminate pasta and rice (substitute potatoes, sweet potatoes, cauliflower rice, courgette spaghetti, etc). Reduce bread quantity, and buy only 'artisan' wholemeal bread (whether wheat, spelt, or rye). Not too much cheese. Cook everything from scratch, as much as possible.
You don't have to make your own cheese (!) or yogurt or tomato puree, etc etc. but do check labels of products for any synthetic ingredients and avoid added sugar.
Eat anything you like within these parameters, i.e. if you want pizza then make it from scratch with fresh ingredients (tomatoes, mozarella, basil, capers, etc). Ditto if you want biscuits (and use unprocessed sugar). Airfryers are great for making healthy chips (try celeriac as well as normal potatoes and sweet potatoes).
I recently lost nearly 3 stone over a one year period following this regime, plus moderate exercise at least 20 mins a day (brisk walking, housework, gardening is fine). No calorie counting. I also drank wine. I was size 16 and am now a 12. Post-menopausal when it's meant to be harder to lose weight. Like you I was eating loads of sugary processed food.
If the above sounds too onerous, then start off with just the no processed/ultra-processed rule, especially avoid processed sugary food, and at least do 50:50 grain rice/cauliflower rice, and 50:50 pasta/courgette spaghetti.